Synthesis of New Spiropyrans With a Polyaromatic or Heteroaromatic Pendant and Their Photochromic Bedhaviors

A series of spiropyrans with a polyaromatic or heteroaromatic pendant was synthesized conveniently.Their photochromic behaviors were investigated with the aid of absorption spectral measurements.The results indicated that the compounds with the same parent spiropyran but different aromatic pendant show significantly different photochromic properties.This may be due to the π-π orbital interaction between the polyaromatic pendant and the open photomerocyanine form of spiropyran.The results obtained are very useful in the molecule design area.     

On a class of least-element complementarity problems

The present paper studies the linear complementarity problem of finding vectorsx andy inR ₊ ⁿ such thatc + Dx + y 0,b – x 0 andx ^T (c + Dx + y) = y ^T (b – x) = 0 whereD is aZ-matrix andb > 0. Complementarity problems of this nature arise, for example, from the minimization of certain quadratic functions subject to upper and lower bounds on the variables. Two least-element characterizations of solutions to the above linear complementarity problem are established first. Next, a new and direct method to solve this class of problems, which depends on the idea of least-element solution is presented. Finally, applications and computational experience with its implementation are discussed.Research partially supported by the National Science Foundation Grant MCS 71-03341 A04 and the Air Force Office of Scientific Research Contract F 44620 14 C 0079.     

Modeling and simulation for a drop-impact analysis of multi-layered printed circuit boards

Multi-layered printed circuit boards (PCBs) contain a multi-layered structure that is suitable for high-speed and high-frequency applications. Hence, they are used extensively in electronic packaging assemblies for high-density applications. However, numerous composite parts and complex material properties of multi-layer PCBs complicate the reliability simulation of PCB model. This paper deals with a finite element analysis intended to describe numerically the behavior of multi-layered multi-materials PCB model (combination of metallic and composite plies) in the drop-impact performance. Through the comparison of physical drop test results, the fully multi-layered model illustrates higher accuracy if compared with that of the traditional simplified isotropic model and orthotropic model. The effects of material properties for the multi-layer PCB under drop-impact shock have also been investigated.     

Voice over wireless local area network

This paper introduces the special issue on voice over wireless local area networks (VoWLAN), which aim to foster interaction among researchers from both academia and industry in networking, wireless communications, and mobile computing. The special issue includes an article investigating the issue of determining an appropriate pricing strategy for VoWLAN provisioning. Also featured are two articles on polling as a solution for supporting real-time traffic over WLANs and another on media optimization network architecture (MONA).     

Existence of positive stationary solutions for a diffusive variable-territory prey–predator model

This paper concerns the existence of positive stationary solutions for a diffusive variable-territory prey–predator model, and completely settles an open problem of Wang and Pang (2009). The main result closes a gap in an earlier result (2011) by the authors.     

Production, Characterization, and Application of an Organic Solvent-Tolerant Lipase Present in Active Inclusion Bodies

An organic solvent-tolerant lipase from Serratia marcescens ECU1010 (rSML) was overproduced in Escherichia coli in an insoluble form. High concentrations of both biomass (50 g cell wet weight/L culture broth) and inclusion bodies (10.5 g/L) were obtained by applying a high-cell-density cultivation procedure. Activity assays indicated that the enzymatic activity of rSML reached 600 U/L. After treatment with isopropyl ether for 12 h, the maximum lipase activity reached 6,000 U/L. Scanning electron microscopy and Fourier transform infrared microspectroscopy revealed the activation mechanism of rSML in the presence of organic solvents. rSML was stable in broad ranges of temperatures and pH values, as well as in a series of organic solvents. Besides, rSML showed the best enantioselectivity for the kinetic resolution of (±)-trans-3-(4-methoxyphenyl)glycidic acid methyl ester. These features render the S. marcescens ECU1010 lipase attractive for biotechnological applications in the field of organic synthesis and pharmaceutical industry.     

Microblogging,friendship maintenance,and life satisfaction among university students: The mediatory role of online self-disclosure

Despite a substantial literature suggests that computer-mediated communication impact individuals’ various psychosocial factors, relatively few studies have elucidated the underlying mechanism behind these associations. Building upon self-disclosure theory and previous studies, the principal purpose of this present research is to systematically explore the relationships among microblog utilization, online self-disclosure, friendship maintenance, and perceived life satisfaction. A web-based survey was implemented using a total of 426 university students in Northwestern China. Structural equation modeling reveals that intensity of microblog use is positively associated with these students’ friendship maintenance and life satisfaction. Additionally, online self-disclosure plays the crucial mediatory role in the relationships between microblog use, quality of relationships, and gratification with life. The results imply that as microbloggers disclosure their inner thoughts or emotional states with other users online, they could foster their friendship maintenance and obtain greater life satisfaction. However, contrary to the expectation, students’ friendship maintenance is not discovered to be a significant predictor of the sense of life satisfaction in the online environment. Overall, these obtained outcomes of the empirical work could offer new insights into the deep comprehending of the social psychological process of microblogging among younger generation in the new media context.